Apparatus and method for in-line planing of lumber using angled abrasive head

Abstract

Method and apparatus for belt sanding of lumber to finish and dimension lumber as rough sawn lumber is moved in single file through the mill. The lumber is moved at an angle of between about 5 to 15 degrees to the axis of the contact drum of a wide belt planer. This angular relationship of the lumber beneath the belt permits the high speed planing without overstressing the abrasive belt.

I claim: 
     
       1. An in-line angle planing apparatus for planing a surface of a workpiece comprising a length of lumber, said apparatus comprising a bed,   conveyor means supported by said bed for carrying a workpiece longitudinally along a linear path across said bed,   support and drive means for an endless abrasive belt comprising a plurality of rolls, one of which is a contact drum having an axis disposed at an angle of between 5 and 15 degrees to said path and having sufficient length to extend across the width of said path at a said angle and support a said belt having a width sufficient to extend across said path, and drive means for driving one of said rolls,   means constraining a said workpiece for movement by said conveyor means longitudinally of said bed and past said contact drum such that said workpiece engages said belt on said contact drum adjacent one end on one side of the axis of said drum and exits adjacent the other end of said drum on the opposite side of said axis and wherein said workpiece contacts and moves across said belt at an angle of between 5 and 15 degrees to the axis of said drum.   
     
     
       2. An apparatus according to claim 1 wherein said conveyor means can carry said workpiece through said means constraining said workpiece at a feed speed exceeding 415 feet per minute. 
     
     
       3. Method of planing a surface of a workpiece comprising a piece of lumber for the purpose of dimensioning the workpiece, said method comprising the steps of advancing the workpiece longitudinally along a predetermined path,   disposing a contact drum with its axis transverse to and across the width of the said path,   driving an endless abrasive belt over a plurality of rolls, one of which is said contact drum, said belt having a width to extend across the width of the said path, and   disposing said contact drum with respect to the direction of said path such that the axis of the contact drum is disposed at an angle between 5 to 15 degrees with respect to the path of the workpiece such that said workpiece contacts the surface of the belt on said drum adjacent one end spaced to one side of the axis thereof and passes beneath the drum and exits adjacent the opposite end of the drum on the side of the axis opposite the side at which it entered, thus the workpiece contacts with the effective width of the abrasive belt as it moves beneath the drum.   
     
     
       4. The method of claim 3 wherein said workpiece has a normal board dimension between 0.5 inch and 12 inches, and the feed rate is at least 3 times faster than at a feed angle perpendicular to the contact drum. 
     
     
       5. The method of claim 3 wherein the abrasive belt has a width of at least 14 inches and the belt is driven at a speed of between 5000 and 12,000 surface feet per minute.